IANAL but pretty sure trademark is based on first provable public use for commercial purposes. You should be able to contest the mark on that basis. Just screenshot the WHOIS record showing you had the domain 7yrs ago and hire a lawyer to write a cease & desist to them. Just because you hold the trademark doesn't make it necessarily defensible if it's proven that it was obtained surreptitiously. Depending on what you learn from the lawyer and how aggressive you want to play it threaten counter suit for damages and escalate.

But agree with all comments: get a lawyer before you do anything.